Friday, August 27, 2010

Butterflies and the Final Pond Mud

This has been a great year for butterflies and now is the time to be watching for southern species that extend their populations into Ohio during the late summer. This is a Little Sulphur, a regular immigrant species found at Blue Jay Barrens. It’s a very flashy butterfly that I may see once or twice each season. This northward expansion is a risky business for species such as the Little Sulphur. These temporary populations are killed by cold winter temperatures and this behavior can appear to do nothing but destroy a lot of butterflies. Species increase their chances of survival by occupying every acceptable habitat they can find and aggressive immigration guarantees that every possible opportunity is taken to improve the long term chances for survival.

As has been the case with many other species this year, the area is thick with Little Sulphurs. These three are probing for the last of the moisture from the drying pond. It’s interesting that the above normal rainfall we were having earlier in the year ended abruptly in mid July and we’ve been in drought mode since then.

I talked earlier about the butterfly’s habit of taking mineral laden moisture from the damp earth. This puddling behavior provides a great opportunity to observe large numbers of butterflies. Each day without rain brings more butterflies into this last bit of moisture left by the disappearing pond.

The pond sediments have shrunk during the drying process, causing cracks to form in the pond bottom. The moisture no longer wicks to the surface as it did when water was more plentiful. These Eastern Tailed Blues have to probe deep to find any moisture.

Many of the Pearl Crescents have taken to probing around the base of plant debris. Apparently the mulching effect of the plant material makes it easier to find moisture near the surface.

The grouping behavior of the different species reminds me of herds of grazing animals moving across the African veldt. Each butterfly species searches for moisture in a slightly different manner and location. So, like those grazing herds, the different species utilize the same resource, but in a manner that eliminates competition. It would be interesting to make enough observations to know whether this separation of species is a normal thing or if it’s just what’s been happening here during the past couple of weeks.

4 comments:

  1. Puddling is such incredible behavior. I guess I've never been in the right place at the right time to see such a phenomenon. I am amazed with these photos! ~karen

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  2. Steve..why are you doing this to me is it because I had buckets of rain and you didn't!! ; }
    This is amazing...I have seem similar happening but it has been a looong time!!
    Sent me a half a bag of those butterflies ( make sure there is a good mix and I"ll get that half a bucket of water to you as soon as possible !! ; }

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  3. I can't say I can recall seeing this group 'puddling' feeding behavour but maybe I haven't been looking at the right time and place. Something new to open my eye up to. Thanks Steve.

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  4. Karen – I hope you do get to see this behavior some time. It’s amazing.

    Why, grammie g, I’m just trying to share this bounty in some small way the best I know how. Just like you generously share the images of the excessive rains you have there.
    I rounded up a half bag of butterflies and sent them winging their way north-east towards Maine. I hope their little brains don’t forget where they’re headed. Let me know when they get there. I’ll be looking for that rain.

    Hi, Frank. I most commonly see this behavior around drying puddles in gravel or dirt roads. The most likely time is late summer about a day or two after a rain.

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